how much horsepower will a tune free up?

Just by looking at the mods in my sig, will a tune benefit me with a noticeable horsepower gain? (SCT chip and dyno tune in the next couple weeks). Or will it mostly just be a driveability gain. This is sort of wishful thinking but i'm hoping for 300rwhp with the tune. Oh and Im having the tuner put on a 73MM MAF at the same time.